New formula for silver testing acid ?

[Andreadb]

Hello!
I recently run out of the acid for silver testing and almost all sellers now only propose a new formula. Apparently legislation has changed and the acid that turns red when in contact with silver is no longer allowed.
However this new acid needs to be placed on the object, where it will leave a white mark if it is silver. The problem is that the white mark is permanent !! It cannot be used on small objects, as the mark would spoil them... And it does not work by scratching some material on a testing stone.
Has somebody else encountered this problem ?
Or can you point me to a seller who still provides the old formula?
Thank you !!
Andrea

[AG2012]

Hi,
Must be niric acid; it leaves milky white spot on sterling or higher.
It actually etches silver; more vigorous polishing is needed.
Whatever acid is used, make sure to file deep enough; that`s golden rule for acid testing.
Regards

[Bahner]

Hello, the old fomula used nitric acid and potassium bichromate (both hazardous) in distilled water. If you get access to these chemicals you may find short films on the internet on how to make the testing solution, which runs under the name of "Schwerter's solution". Be extremely careful !!! And please take into account that this method of testing silver is quite unreliable. Regards, Bahner

[Andreadb]

Thank you for your replies.
I do not think I have access to the base elements to make up the test liquid, nor would I try to handle and mix dangerous substances...

How do you test small silver objects? Where do you buy the ready to use formula, the one that turns red when in contact with silver (on the test stone!) ?
Regards
Andrea

[AG2012]

1. Old kits (red reaction) are still available online.
3. If the object is very small, experience is needed; 10 x loupe fixed to the eye (the way watchmakers do). Then file deep enough to expose base metal and apply small drop of acid. There will be difference between bright red if silver, (silver plated surface,too) and dull brownish or green on base metal. Experience is needed and testing is not reliable, plus you are about to damage jewelry. Rubbing on black stone is even less reliable.
Search for marks.
Regards

[Andreadb]

Good afternoon,
I only found one seller from UK who provides the old formula; bought one bottle and it never arrived...Can you point me to a reliable supplier?

I only use the acids on those items that do not have a hallmark; I know that the testing is not 100% reliable, but if there are no hallmarks and the magnet does not attract the object, what other options are there ? How elese can you prove if it is silver or not?
Regards
Andrea

[amena]

It is a big problem
Someone told me that this new liquid is not very reliable and we are all a little annoyed.
The liquid sold in Italy was based on sulfuric acid and potassium dichromate and worked well with 800/000 silver.
I tried the liquid based on nitric acid, bought in USA, but sometimes it did not give good results on the 800/1000, perhaps because it is calibrated on sterling.
Could it be enough to dilute it a little?
Even the recipes I find on the internet are always based on nitric acid.
Anyone know the recipe with sulfuric acid?
Regards
Amena